Dehydrogenation and rehydrogenation of a 0.62LiBH4-0.38NaBH4 mixture with nano-sized Ni

Research output: Contribution to journalArticlepeer-review

Authors

  • Michael Heere
  • Christos Paterakis
  • Magnus Sørby
  • Bjørn Hauback

Colleges, School and Institutes

External organisations

  • Institute for Energy Technology, Kjeller

Abstract

The dehydrogenation reaction pathway of a 0.91 (0.62LiBH4-0.38NaBH4)-0.09Ni mixture in the temperature range of 25–650 °C in flowing Ar and the cycling stability in H2 are presented. No H2 is released immediately after melting at 225 °C. The major dehydrogenation occurs above 350 °C. Adding nano-sized Ni reduces the dehydrogenation peak temperatures by 20–25 °C, leading to three decomposition steps where Ni4B3 and Li1.2Ni2.5B2 are found in the major dehydrogenation products for the 1st and the 3rd step; whilst the Ni-free mixture decomposes through a two-step decomposition pathway. A total of 8.1 wt% of hydrogen release from the 0.91 (0.62LiBH4-0.38NaBH4)-0.09Ni mixture is achieved at 650 °C in Ar. This mixture has a poor hydrogen cycling stability as its reversible hydrogen content decreases from 5.1 wt% to 1.1 wt% and 0.6 wt% during three complete desorption-absorption-cycles. However, the addition of nano-sized Ni facilitates the reformation of LiBH4.

Details

Original languageEnglish
JournalInternational Journal of Hydrogen Energy
Early online date29 May 2018
Publication statusE-pub ahead of print - 29 May 2018

Keywords

  • Hydrogen storage, Nanomaterial, Eutectic borohydrides, Dehydrogenation, Rehydrogenation, Reaction pathways